According to the theory of punctuated equilibrium which event could lead to speciation?

A. An extremely cold winter occurs.

B. A meteor strikes Earth.

C. One species changes behavior patterns.

D. A geographic barrier separates species.

A spore stalk grows from the gametophyte of a moss. What is the next step in its life cycle? A) Gametophyte B) Meiosis C) Gametes D) Mitosis

Which of the following is NOT an effect of histone acetylation? a. the positive charges on lysines are neuralized b. conversion of the beads on a string to the 30 nM fiber c. DNA binding to the nucleosomes is weakened d. recruitment of SWI/SNF e.

What occurs during the S (synthesis) phase of interphase. A. growth of the cell B. replication of DNA C. division of the cell

Using your knowledge of tissues, what type of tissue do you think makes up the three layers of membrane you encountered in your muscle?

Under which of the following conditions will speciation not occur? a. Logging operations in a forest cut a single population of beetles in two so that they can no longer mix. b.

Genes are located on what and each gene controls a specific what

Refer to the introductory section of the chapter entitled "Earthbound Extraterrestrial? Or Just Another Microbe in the Mud?" Which of the following statements would be a feasiblehypothesis? A. If microbes do not have phosphorus, they will die. B.

Processes and packages proteins and lipids in the cell

The largest reservoir of nitrogen is found in which of the following? A. earthworms B. marine organisms C. atmosphere D. trees

An oncogene is: Select one: a viral gene with no relation to the host cells genes. b. a mutated form of a proto-oncogene. c. a bacterial gene that causes cancer in the host. d. always seen in human cancer cells. e.